Machines such as end loaders, back hoes, mobile cranes and the like commonly include hydraulic drive motors for propelling the machines and hydraulic cylinders for effecting movement of various movable implements or work pieces of the machines. The hydraulic drive motors and hydraulic cylinders are commonly controlled by manually operated hydraulic control valves such as foot pedals or control levers mechanically coupled to the control valves.
In one prior arrangement illustrated in U.S. Pat. No. 3,576,302, issued Apr. 27, 1971, a foot pedal of an aircraft is used to produce solid state electrical signals which can, in turn, be used to control operation of components of the aircraft.
Attention is also directed to rigid joystick control devices of the type for producing electrical control signals, such as rigid joysticks illustrated in U.S. Pat. No. 4,046,005, issued Sept. 6, 1977 to Goroski and U.S. Pat. No. 3,454,920, issued July 8, 1969 to Mehr. Attention is further directed to U.S. Pat. No. 2,909,764, issued Oct. 20, 1959 to Chambers; U.S. Pat. No. 2,943,480, issued July 5, 1960 to Nelting; U.S. Pat. No. 3,124,770, issued Mar. 10, 1964 to Ciavatta; U.S. Pat. No. 3,234,787, issued Feb. 15, 1966 to Ruge; U.S. Pat. No. 3,513,431, issued May 19, 1970 to Kovacs; and U.S. Pat. No. 4,554,920, issued Nov. 26, 1985 to Baker.